Get rid of pgpass_from_client tracking inside libpq --- given the conclusion

that presence of the password in the conninfo string must be checked *before*
risking a connection attempt, there is no point in checking it afterwards.
This makes the specification of PQconnectionUsedPassword() a bit simpler
and perhaps more generally useful, too.

doc/src/sgml/libpq.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.264 2008/09/22 13:55:13 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.265 2008/09/22 14:21:44 tgl Exp $ -->
 
 <chapter id="libpq">
  <title><application>libpq</application> - C Library</title>
@@ -1201,7 +1201,6 @@ PQconninfoOption *PQconninfoParse(const char *conninfo, char **errmsg);
        <synopsis>
         int PQconnectionNeedsPassword(const PGconn *conn);
        </synopsis>
-
       </para>
 
       <para>
@@ -1216,19 +1215,16 @@ PQconninfoOption *PQconninfoParse(const char *conninfo, char **errmsg);
      <listitem>
       <para>
        Returns true (1) if the connection authentication method
-       used a caller-supplied password. Returns false (0) if not.
+       used a password. Returns false (0) if not.
 
        <synopsis>
         int PQconnectionUsedPassword(const PGconn *conn);
        </synopsis>
-
       </para>
 
       <para>
-       This function detects whether a password supplied to the connection
-       function was actually used.  Passwords obtained from other
-       sources (such as the <filename>.pgpass</> file) are not considered
-       caller-supplied.
+       This function can be applied after either a failed or successful
+       connection attempt to detect whether the server demanded a password.
       </para>
      </listitem>
     </varlistentry>

src/interfaces/libpq/fe-connect.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.361 2008/09/22 13:55:14 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.362 2008/09/22 14:21:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -232,8 +232,7 @@ static PGconn *makeEmptyPGconn(void);
 static void freePGconn(PGconn *conn);
 static void closePGconn(PGconn *conn);
 static PQconninfoOption *conninfo_parse(const char *conninfo,
-			   PQExpBuffer errorMessage, bool use_defaults,
-			   bool *password_from_string);
+			   PQExpBuffer errorMessage, bool use_defaults);
 static char *conninfo_getval(PQconninfoOption *connOptions,
 				const char *keyword);
 static void defaultNoticeReceiver(void *arg, const PGresult *res);
@@ -377,8 +376,7 @@ connectOptions1(PGconn *conn, const char *conninfo)
 	/*
 	 * Parse the conninfo string
 	 */
-	connOptions = conninfo_parse(conninfo, &conn->errorMessage, true,
-								 &conn->pgpass_from_client);
+	connOptions = conninfo_parse(conninfo, &conn->errorMessage, true);
 	if (connOptions == NULL)
 	{
 		conn->status = CONNECTION_BAD;
@@ -474,7 +472,6 @@ connectOptions2(PGconn *conn)
 										conn->dbName, conn->pguser);
 		if (conn->pgpass == NULL)
 			conn->pgpass = strdup(DefaultPassword);
-		conn->pgpass_from_client = false;
 	}
 
 	/*
@@ -560,14 +557,12 @@ PQconninfoOption *
 PQconndefaults(void)
 {
 	PQExpBufferData errorBuf;
-	bool		password_from_string;
 	PQconninfoOption *connOptions;
 
 	initPQExpBuffer(&errorBuf);
 	if (errorBuf.data == NULL)
 		return NULL;			/* out of memory already :-( */
-	connOptions = conninfo_parse("", &errorBuf, true,
-								 &password_from_string);
+	connOptions = conninfo_parse("", &errorBuf, true);
 	termPQExpBuffer(&errorBuf);
 	return connOptions;
 }
@@ -668,7 +663,6 @@ PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions,
 		if (conn->pgpass)
 			free(conn->pgpass);
 		conn->pgpass = strdup(pwd);
-		conn->pgpass_from_client = true;
 	}
 
 	/*
@@ -3127,7 +3121,6 @@ PQconninfoOption *
 PQconninfoParse(const char *conninfo, char **errmsg)
 {
 	PQExpBufferData errorBuf;
-	bool		password_from_string;
 	PQconninfoOption *connOptions;
 
 	if (errmsg)
@@ -3135,8 +3128,7 @@ PQconninfoParse(const char *conninfo, char **errmsg)
 	initPQExpBuffer(&errorBuf);
 	if (errorBuf.data == NULL)
 		return NULL;			/* out of memory already :-( */
-	connOptions = conninfo_parse(conninfo, &errorBuf, false,
-								 &password_from_string);
+	connOptions = conninfo_parse(conninfo, &errorBuf, false);
 	if (connOptions == NULL && errmsg)
 		*errmsg = errorBuf.data;
 	else
@@ -3152,12 +3144,10 @@ PQconninfoParse(const char *conninfo, char **errmsg)
  * left in errorMessage.
  * Defaults are supplied (from a service file, environment variables, etc)
  * for unspecified options, but only if use_defaults is TRUE.
- * *password_from_string is set TRUE if we got a password from the
- * conninfo string, otherwise FALSE.
  */
 static PQconninfoOption *
 conninfo_parse(const char *conninfo, PQExpBuffer errorMessage,
-			   bool use_defaults, bool *password_from_string)
+			   bool use_defaults)
 {
 	char	   *pname;
 	char	   *pval;
@@ -3168,8 +3158,6 @@ conninfo_parse(const char *conninfo, PQExpBuffer errorMessage,
 	PQconninfoOption *options;
 	PQconninfoOption *option;
 
-	*password_from_string = false;			/* default result */
-
 	/* Make a working copy of PQconninfoOptions */
 	options = malloc(sizeof(PQconninfoOptions));
 	if (options == NULL)
@@ -3326,12 +3314,6 @@ conninfo_parse(const char *conninfo, PQExpBuffer errorMessage,
 			free(buf);
 			return NULL;
 		}
-
-		/*
-		 * Special handling for password
-		 */
-		if (strcmp(option->keyword, "password") == 0)
-			*password_from_string = (option->val[0] != '\0');
 	}
 
 	/* Done with the modifiable input string */
@@ -3597,7 +3579,7 @@ PQconnectionUsedPassword(const PGconn *conn)
 {
 	if (!conn)
 		return false;
-	if (conn->password_needed && conn->pgpass_from_client)
+	if (conn->password_needed)
 		return true;
 	else
 		return false;

src/interfaces/libpq/libpq-int.h

@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-int.h,v 1.133 2008/09/19 16:40:40 tgl Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-int.h,v 1.134 2008/09/22 14:21:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -290,7 +290,6 @@ struct pg_conn
 	char	   *dbName;			/* database name */
 	char	   *pguser;			/* Postgres username and password, if any */
 	char	   *pgpass;
-	bool		pgpass_from_client;	/* did password come from connect args? */
 	char	   *sslmode;		/* SSL mode (require,prefer,allow,disable) */
 #if defined(KRB5) || defined(ENABLE_GSS) || defined(ENABLE_SSPI)
 	char	   *krbsrvname;		/* Kerberos service name */